The blower door system enables one to identify leaks in a building.These include humid sections of structural elements, problems with draughts, impairments to a building’s noise-abatement properties, and deteriorated air quality caused by pollutants.

To detect a building’s leaks, first the entrance is sealed with heavy canvass.Using a ventilator built into the canvass, below-atmospheric pressure is created within the building, followed by above-atmospheric pressure.

The air regeneration coefficient is measured at various pressure differentials and may not exceed certain ceilings.


The higher the building’s density, the lower the volume flow.If the air regeneration coefficient does not meet the required standard, one must search for leaks.This is done with artificial fog, which makes the leaks visible.These tests are all the more important when installing a ventilation system with heat recovery.